UPDATE: Zenith Clarifies Zodiac 601 Model Number Change
The Zodiac CH 601 XL
Zenith Aircraft Company issued a clarification regarding the designation of the Zodiac CH 601 XL after a required design upgrade is completed. With the design changes applied, the aircraft should now be referred to as Model CH 601 XL B to denote it has received the upgrade. However, Zenith is reminding builders to register their aircraft with the FAA using the exact same model name as the one shown on the FAA's listing of eligible kits - that is, CH 601 XL.
The FAA says an upgrade kit (6-ZU) offered by Zenith Aircraft Company to address concerns about the design of the Zodiac CH 601 XL meets the requirements of the 51 percent rule. The kit was offered in 2009 after several accidents involving structural failures in a number of aircraft. In a statement, Zenith pointed to an FAA Special Team Report that concluded that the string of accidents had no one cause but was a combination of design and operational factors.
601 model number changes, FAA model number remains the same
Zenith says that the upgrade significantly beefs up the design in an effort to restore confidence within builder and owner ranks while also highlighting the aircraft’s design limitations. Once the upgrade kit is installed the aircraft is re-designated by Zenith as the CH 601 XL B; however, the registered model name must match the model name on the FAA’s list of eligible kits.
In late 2009 AMD issued a safety directive for all production versions (S-LSA) of the 601 XL and 650 and halted airworthiness certification on all aircraft, both production and amateur-built (E-LSA) models, until the upgrade was made. Owners of amateur-built aircraft already certificated were strongly encouraged not to fly their aircraft until the changes were made.
There are many Zodiac XL aircraft still currently under construction by amateur builders across the country and the FAA's re-evaluation of the kit assures builders that their kit aircraft, with the installed upgrade package kit, still meet the 51 percent rule, a requirement for registration as "experimental amateur-built."
Zenith Aircraft Company has since replaced the Zodiac XL model with the new CH 650 model, which introduced a new, larger bubble canopy and new styling, including a swept-back rudder tail design. The all-metal CH 650 kit may be built from plans (blueprints) or from a complete kit. The CH 650 design meets the definition for LSA, meaning it can be operated with a sport pilot certificate, and a factory-built S-LSA model is also available.